SWIPT for Max-Min Fair Multi-Group Multicast Beamforming through Power Splitting

In this paper, simultaneous wireless information and power transfer (SWIPT) is considered in the context of multi-group multicast beamforming. A base station transmits more than one multicast streams to the groups of users where each group targets its own information signal. Users have single antenna and the received radio frequency (RF) signals are split into two for both information decoding and energy harvesting through a power splitter device. The aim is to maximize the minimum signal-to-interference-plus-noise ratio (SINR) among all the users while satisfying the harvesting power demands and the maximum transmission power constraint at the base station. The max-min fair beamforming problem is not convex. Hence the problem is first reformulated in terms of new variables in an exact manner and successive convex approximation (SCA) is applied after some transformations. Two iterative algorithms are proposed the first of which relies on a previous convex approximation technique applied on the reformulated problem. The second algorithm introduces a new reformulation where less number of convex approximations are required. Simulation results show that this new approach is very effective and results better performance in comparison.